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1.
基于SoPC的节流控制系统为压井远程智能监控系统的一部分.该系统采用了在FPGA中加入NIOS II嵌入式软核CPU的SoPC技术,可实现压井过程中对多级节流管汇的控制.论述了液动平板阀和节流阀的控制原理,控制电路的设计方法和控制流程.该系统运行可靠,控制灵敏性高,与以往的控制系统相比,体积更小,功耗更低,具有较好的应用前景.  相似文献   

2.
江汉石油管理局第四石油机械厂(简管四机厂)是中国石油钻采设备的主要制造厂家,产吕覆盖钻井、采油、海洋石油钻采、高压管汇等领域,产品的技术性能和质量水平在国内同行业中居领先地位,并有多项产品打入国际市场.四机厂的主要工艺特点是小批量、多品种、基本上按订单生产,属典型的离散制造型企业.2001年10月四机厂与北京清软英泰信息技术有限公司合作共同建设四机厂的PDM系统,迄今为止,四机厂的PDM项目处于第三期工程.PDM系统建成后,大大提高了设计效率和企业资源的综合利用程度,为客户订单的顺利完成提供了保障.  相似文献   

3.
分析当前主流电子镇流器控制芯片的优缺点,提出了一种适用于功率在20W以下节能灯控制芯片的设计方案.采用常规的CMOS铝栅工艺.整个控制芯片由主芯片和高压管驱动两块芯片组成,两管间通过自举电容耦合.自举电容起的作用:(1)隔离高压(2)传输高压功率管的控制信号.此设计方案的难点是设计出符合上述设计要求的高压管驱动芯片.此款芯片采用6μm CMOS铝栅工艺模型,经仿真验证,现已通过MPW流片成功.测试各项指标都达到设计要求.  相似文献   

4.
江汉石油管理局第四石油机械厂(简称四机厂)是中国石油钻采设备的主要制造厂家,产品覆盖钻井、采油、海洋石油钻采、高压管汇等领域,产品的技术性能和质量水平在国内同行业中居领先地位,并有多项产品打入国际市场。四机厂的主要工艺特点是小批量、多品种、基本上按订单生产,属典型的离散制造型企业。2001年10月四机厂与北京清软英泰信息技术有限公司合作共同建设四机厂的PDM系统,  相似文献   

5.
谢冲  唐洋  严永发 《控制工程》2016,(3):361-365
在石油天然气井控作业实施过程中,目前存在设备操作繁琐、人员协同要求高、关井时间过长和易发生误操作等不足之处,因此,有必要设计一套井控设备的无线远程集中控制系统,将防喷器远控台和节流管汇的单独分散控制设计为集中控制。该设计优化了控制装置的结构布局,变多人操作为一人集中操作,避免了协同操作要求,降低了人为误操作风险。并且为系统增设了一套无线远程集中控制装置,提高了其应急处理能力。同时,该系统还具有对井控设备关键参数进行实时采集、显示和存储的功能。最后通过实验对该系统功能进行了验证,其完全满足设计要求,有效解决了上述工程问题。  相似文献   

6.
为了解决心脏流体运动状态的可视化描述问题,根据心脏流场超声图像的特点,提出一种基于彩色多普勒图像信息的心脏流体运动平面流线可视化描述方法.该方法采用点源和点汇表示二维观测区域的三维流动,通过拓展流函数计算原理实现多普勒流函数值的计算;以点源和点汇作为平面流线的起点和终点,根据同一流线上多普勒流函数值相等的原理绘制平面流线;选取平面流线中的封闭曲线获得心脏流场内涡流流线图.实验结果表明,文中方法能够对彩色多普勒图像中的流体运动状态进行有效的可视化描述,并能有效地描述心脏流体的涡流运动状态,为心脏流体运动状态的有效可视化观察和精确量化评价提供了一种新方法.  相似文献   

7.
本文将负刚度元件集成到惯容型非线性能量汇中构成负刚度惯容型非线性能量汇,并将此装置应用到整星结构,讨论其减振效果.基于最大幅值减振百分比展示了负刚度惯容型非线性能量汇的减振性能,并通过对比讨论了负刚度元件对惯容型非线性能量汇减振性能的影响.最后讨论了负刚度惯容型非线性能量汇的参数影响及其优化.研究结果表明,作用于整星系统中的新型负刚度惯容型非线性能量汇具有很好的减振性能.  相似文献   

8.
论文提出了一种基于速率的IP接入网流量控制算法的设计思路。其目的是通过源端数据发送率的调节,提高接入网中汇节点的吞吐率;降低数据包的平均时延。算法可分成两个部分,分别驻留于汇结点端和源端。汇结点端完成优化计算,为源端数据发送率的变化做决策。源端根据来自汇结点的反馈信号调节自身的发送速率。  相似文献   

9.
对比某重型载货汽车前轴台架刚度试验计算值与试验值,发现简化边界导致位移计算值偏大.对前轴台架试验的夹具进行测量并在Abaqus中建立其实体有限元模型,使得位移计算值和试验值误差在2.5%以内,从而保证疲劳计算输入的应力谱的准确性.根据前轴疲劳试验标准QC/T513—1999规定的工况,利用FEMFAT计算某重型载货汽车前轴的疲劳寿命,并与试验得到的破坏位置和寿命进行对比,验证疲劳计算的可靠性.在对前轴应力和疲劳计算结果进行分析的基础上,提出提高前轴疲劳寿命的改进建议.  相似文献   

10.
无线传感器网络在文物保护中的应用   总被引:1,自引:0,他引:1  
无线传感器网络是计算、通信和传感器三项技术结合的产物,被视为环境监测和建设监测的一个发展方向,有着广泛的应用领域,文物保护是其潜在的应用领域之一.介绍无线传感器网络的特点及其在文物保护中应用的必要性,提出博物馆文物保护系统无线传感器网络构建方案,以及无线传感器网络节点、汇节点和博物馆监控中心软件等部分的设计方案.与传统的文物保护系统相比,该系统具有易于扩充,测量准确等特点.  相似文献   

11.
本文阐述了一种对共模扼流圈的的改进方法,及其在视频信号传输中的应用与实现。  相似文献   

12.
Flow limitation in the airways is a fundamental process constituting the maximal expiratory flow-volume curve. Its location is referred to as the choke point. In this work, expressions enabling the calculation of critical flows in the case of wave-speed, turbulent or viscous limitation were derived. Then a computational model for the forced expiration from the heterogeneous lung was used to analyse the regime and degree of flow limitation as well as movement and arrangement of the choke points. The conclusion is that flow limitation begins at similar time in every branch of the bronchial tree developing a parallel arrangement of the choke points. A serial configuration of flow-limiting sites is possible for short time periods in the case of increased airway heterogeneity. The most probable locations of choke points are the regions of airway junctions. The wave-speed mechanism is responsible for flow choking over most of vital capacity and viscous dissipation of pressure for the last part of the test. Turbulent dissipation, however, may play a significant role as a supporting factor in transition between wave-speed and viscous flow limitation.  相似文献   

13.
随着Bit Torrent系统的广泛使用,Bit Torrent引起了学术界的极大关注。已有的研究工作主要集中于Bit Torrent测量、建模和算法等方面。该文通过对BT系统的阻塞算法的分析研究,指出存在的问题,为提高阻塞算法研究提供依据。  相似文献   

14.
This paper presents a nonlinear model predictive control scheme for stabilizing the well pressure during oil well drilling. While drilling, a fluid is pumped through the drill string and the drill bit, and is returning through the annulus between the drilled well and the drill string. Varying reservoir conditions and fluctuation in circulation flow rates cause sudden variations in the pressure conditions along the well. To compensate for these pressure fluctuations, the annulus choke valve opening can be adjusted. The proposed control scheme is based on a first-principles two-phase flow model using spatial discretization of the complete well. The optimal future choke settings are found using the Levenberg–Marquardt optimization algorithm. This control scheme is evaluated against two other control methods, a manual control scheme and a standard feed-back PI-control scheme of the choke valve with feed-forward control of the pump rates. The PI-control parameters are found using the Ziegler–Nichols closed-loop method based on simulations from a low-order model. The results show that both the PI-control scheme and the model predictive control scheme are superior to manual control. However, the PI-control scheme requires that the control parameters are re-designed when the operating conditions are deviating from the original design conditions. The model predictive control scheme will perform within the operating limits as long as the detailed model is able to describe the actual conditions of the well.  相似文献   

15.
This paper presents an evaluation of various control methods to be used during drilling operations where an unexpected gas influx occurs. In the event of an unexpected gas influx the current industry procedure is to control the pressure in the well manually. The drilling industry term for this manual procedure is well control. The focus of the paper is threefold. Firstly, to design an automatic sequence which is similar to the existing manual procedure. Secondly, to evaluate three different control algorithms for pressure control during an unexpected gas influx, and thirdly, to evaluate control parameter tuning needed when implementing different control algorithms.The control methods have been evaluated on various drilling scenarios with unexpected gas influx, referred to as a kick. After a kick of reservoir gas has entered the well, automatic control of the well control choke and rig pump is applied to compensate for pressure fluctuations while circulating out the gas. A PI controller is designed to stabilize the well pressure by controlling the well control choke, an internal model controller (IMC) controls the pressure by manipulating the choke and the rig pump flowrate, and a model predictive controller (MPC) uses coordinated control of the choke and the pump flowrate to stabilize the well pressure. The model based controllers use a simple first order model of the well. Simulations are performed using a detailed flow model of the well to test the controller performance and robustness. Several cases with different amounts of gas influx are investigated.The simulations show that it is feasible to control the pressure using automatic control of the choke valve and pump during an unexpected gas influx by use of all the presented control methods. The control methods are robust against changes in process conditions and disturbances, as they are able to handle several pressure levels and gas volumes without requiring re-tuning. However, since the pressure dynamics in the well are influenced when gas is entering the well, the model based controllers could probably be further improved if the models were updated after the gas influx occurred.The results indicate that adaption of the automatic sequence to the current manual procedure is applicable. However, to avoid a reduction in downhole pressure when stopping the pump and shutting in the well, the automatic sequence may be further improved beyond what is feasible with manual operation.  相似文献   

16.
以某SUV车型为研究对象,通过Isight集成Sculptor和FLUENT建立优化平台,在Sculptor中建立控制体,与SUV几何模型建立映射关系;将阻风板的高度和安装角度参数化,并应用Isight的DOE拉丁超立方设计方法创建实验样本点.在此基础上,用Isight驱动FLUENT进行仿真计算并建立Kriging近似模型,得到目标函数风阻系数与变量高度和角度之间的关系.采用多岛遗传算法对近似模型寻找最优解.优化结果表明,通过对阻风板的优化,其阻力因数下降6.1%.  相似文献   

17.
关联规则在公安情报信息系统中的应用   总被引:2,自引:0,他引:2  
针对Apriori算法效率的不足,提出了适合关系数据库中的关联规则挖掘的IMM_Apriori算法。通过对基于矩阵的算法进行改进,引入删除压缩技术提高了算法性能,有效地解决了Apriori算法在发现频繁2-项集时的效率瓶颈问题,并从理论上证明了算法的正确性和可行性。通过在公安情报信息系统中的实际应用,验证了算法良好的适应性和可扩展性。  相似文献   

18.
基于谱图理论的流形学习算法   总被引:38,自引:4,他引:38  
流形学习的主要目标是发现嵌入在高维数据空间的低维光滑流形.近年来基于谱图理论的学习算法受到研究者的广泛关注.介绍了流形与流形学习的关系,着重研究了几种有代表性的基于谱图理论的流形学习算法,并对算法进行了比较分析,最后进行总结和对进一步的研究做了展望.  相似文献   

19.
BitTorrent采用基于速率的Tit-For-Tat(Rate-based TFT)阻塞算法和乐观激活(Optimistic Unchoke,OU)算法为节点选择策略:上传节点采用Rate-based TFT算法选择为自身提供文件块上传速度最快的4个请求节点为下载节点,采用OU算法随机选择其他1个请求节点为下载节点...  相似文献   

20.
提出Dirichlet混合多项式(DCM)流形,并利用DCM流形可与正半球流形建立同胚和等距关系的性质,通过拉回映射将正半球流形的测地距离映射为DCM流形的测地距离,从而在DCM流形上建立距离度量,构建统计流形上的Dirichlet混合多项式扩散核和Dirichlet混合多项式倒排文档频率(DCMIDF)扩散核.利用WebKB Top4和20 Newsgroups语料库上进行实验,DCM流形能比欧氏空间更能准确地描述文本.与多项式核支持向量机算法、,负测地距离核支持向量机算法相比,实验结果显示文中基于DCM扩散核和DCMIDF扩散核的支持向量机算法可取得良好的文本分类效果.  相似文献   

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